Prostomium weekley incised. 2 pairs of eyes in juveniles may be lost with age. No pigmentation, except faint line along feeding groove. Modified spines on chaetiger 5 falcate hooks with accessory tooth. Bidentate hooded hooks start on chaetiger 7, 8-10 hooks per ramus. Branchiae start on chaetiger 7. No specialized notochaetae on posterior chaetigers. Pygidium large, saucer-shaped, dorsally incised.
30 mm for 100 segments
South Africa: Northwestern, southwestern and southeastern coasts. Namibia
East and west coasts of USA (Type locality Connecticut), Hawai’i, Australia, New Zealand, Japan, Korea, Brazil, Venezuela, Mexico
Only boring into farmed oysters.
Identity needs to be clarified, molecular evidence and distribution indicates that it is alien.